// This file defines a number of helpers for wiring up user input to
// table-related functionality.

import {Slice, Fragment} from "prosemirror-model"
import {Selection, TextSelection} from "prosemirror-state"
import {keydownHandler} from "prosemirror-keymap"

import {key, nextCell, cellAround, inSameTable,
        isInTable, selectionCell} from "./util"
import {CellSelection} from "./cellselection"
import {TableMap} from "./tablemap"
import {pastedCells, fitSlice, clipCells, insertCells} from "./copypaste"
import {tableNodeTypes} from "./schema"

export const handleKeyDown = keydownHandler({
  "ArrowLeft": arrow("horiz", -1),
  "ArrowRight": arrow("horiz", 1),
  "ArrowUp": arrow("vert", -1),
  "ArrowDown": arrow("vert", 1),

  "Shift-ArrowLeft": shiftArrow("horiz", -1),
  "Shift-ArrowRight": shiftArrow("horiz", 1),
  "Shift-ArrowUp": shiftArrow("vert", -1),
  "Shift-ArrowDown": shiftArrow("vert", 1),

  "Backspace": deleteCellSelection,
  "Mod-Backspace": deleteCellSelection,
  "Delete": deleteCellSelection,
  "Mod-Delete": deleteCellSelection
})

function maybeSetSelection(state, dispatch, selection) {
  if (selection.eq(state.selection)) return false
  if (dispatch) dispatch(state.tr.setSelection(selection).scrollIntoView())
  return true
}

function arrow(axis, dir) {
  return (state, dispatch, view) => {
    let sel = state.selection
    if (sel instanceof CellSelection) {
      return maybeSetSelection(state, dispatch, Selection.near(sel.$headCell, dir))
    }
    if (axis != "horiz" && !sel.empty) return false
    let end = atEndOfCell(view, axis, dir)
    if (end == null) return false
    if (axis == "horiz") {
      return maybeSetSelection(state, dispatch, Selection.near(state.doc.resolve(sel.head + dir), dir))
    } else {
      let $cell = state.doc.resolve(end), $next = nextCell($cell, axis, dir), newSel
      if ($next) newSel = Selection.near($next, 1)
      else if (dir < 0) newSel = Selection.near(state.doc.resolve($cell.before(-1)), -1)
      else newSel = Selection.near(state.doc.resolve($cell.after(-1)), 1)
      return maybeSetSelection(state, dispatch, newSel)
    }
  }
}

function shiftArrow(axis, dir) {
  return (state, dispatch, view) => {
    let sel = state.selection
    if (!(sel instanceof CellSelection)) {
      let end = atEndOfCell(view, axis, dir)
      if (end == null) return false
      sel = new CellSelection(state.doc.resolve(end))
    }
    let $head = nextCell(sel.$headCell, axis, dir)
    if (!$head) return false
    return maybeSetSelection(state, dispatch, new CellSelection(sel.$anchorCell, $head))
  }
}

function deleteCellSelection(state, dispatch) {
  let sel = state.selection
  if (!(sel instanceof CellSelection)) return false
  if (dispatch) {
    let tr = state.tr, baseContent = tableNodeTypes(state.schema).cell.createAndFill().content
    sel.forEachCell((cell, pos) => {
      if (!cell.content.eq(baseContent))
        tr.replace(tr.mapping.map(pos + 1), tr.mapping.map(pos + cell.nodeSize - 1),
                   new Slice(baseContent, 0, 0))
    })
    if (tr.docChanged) dispatch(tr)
  }
  return true
}

export function handleTripleClick(view, pos) {
  let doc = view.state.doc, $cell = cellAround(doc.resolve(pos))
  if (!$cell) return false
  view.dispatch(view.state.tr.setSelection(new CellSelection($cell)))
  return true
}

export function handlePaste(view, _, slice) {
  if (!isInTable(view.state)) return false
  let cells = pastedCells(slice), sel = view.state.selection
  if (sel instanceof CellSelection) {
    if (!cells) cells = {width: 1, height: 1, rows: [Fragment.from(fitSlice(tableNodeTypes(view.state.schema).cell, slice))]}
    let table = sel.$anchorCell.node(-1), start = sel.$anchorCell.start(-1)
    let rect = TableMap.get(table).rectBetween(sel.$anchorCell.pos - start, sel.$headCell.pos - start)
    cells = clipCells(cells, rect.right - rect.left, rect.bottom - rect.top)
    insertCells(view.state, view.dispatch, start, rect, cells)
    return true
  } else if (cells) {
    let $cell = selectionCell(view.state), start = $cell.start(-1)
    insertCells(view.state, view.dispatch, start, TableMap.get($cell.node(-1)).findCell($cell.pos - start), cells)
    return true
  } else {
    return false
  }
}

export function handleMouseDown(view, startEvent) {
  if (startEvent.ctrlKey || startEvent.metaKey) return

  let startDOMCell = domInCell(view, startEvent.target), $anchor
  if (startEvent.shiftKey && (view.state.selection instanceof CellSelection)) {
    // Adding to an existing cell selection
    setCellSelection(view.state.selection.$anchorCell, startEvent)
    startEvent.preventDefault()
  } else if (startEvent.shiftKey && startDOMCell &&
             ($anchor = cellAround(view.state.selection.$anchor)) != null &&
             cellUnderMouse(view, startEvent).pos != $anchor.pos) {
    // Adding to a selection that starts in another cell (causing a
    // cell selection to be created).
    setCellSelection($anchor, startEvent)
    startEvent.preventDefault()
  } else if (!startDOMCell) {
    // Not in a cell, let the default behavior happen.
    return
  }

  // Create and dispatch a cell selection between the given anchor and
  // the position under the mouse.
  function setCellSelection($anchor, event) {
    let $head = cellUnderMouse(view, event)
    let starting = key.getState(view.state) == null
    if (!$head || !inSameTable($anchor, $head)) {
      if (starting) $head = $anchor
      else return
    }
    let selection = new CellSelection($anchor, $head)
    if (starting || !view.state.selection.eq(selection)) {
      let tr = view.state.tr.setSelection(selection)
      if (starting) tr.setMeta(key, $anchor.pos)
      view.dispatch(tr)
    }
  }

  // Stop listening to mouse motion events.
  function stop() {
    view.root.removeEventListener("mouseup", stop)
    view.root.removeEventListener("dragstart", stop)
    view.root.removeEventListener("mousemove", move)
    if (key.getState(view.state) != null) view.dispatch(view.state.tr.setMeta(key, -1))
  }

  function move(event) {
    let anchor = key.getState(view.state), $anchor
    if (anchor != null) {
      // Continuing an existing cross-cell selection
      $anchor = view.state.doc.resolve(anchor)
    } else if (domInCell(view, event.target) != startDOMCell) {
      // Moving out of the initial cell -- start a new cell selection
      $anchor = cellUnderMouse(view, startEvent)
      if (!$anchor) return stop()
    }
    if ($anchor) setCellSelection($anchor, event)
  }
  view.root.addEventListener("mouseup", stop)
  view.root.addEventListener("dragstart", stop)
  view.root.addEventListener("mousemove", move)
}

// Check whether the cursor is at the end of a cell (so that further
// motion would move out of the cell)
function atEndOfCell(view, axis, dir) {
  if (!(view.state.selection instanceof TextSelection)) return null
  let {$head} = view.state.selection
  for (let d = $head.depth - 1; d >= 0; d--) {
    let parent = $head.node(d), index = dir < 0 ? $head.index(d) : $head.indexAfter(d)
    if (index != (dir < 0 ? 0 : parent.childCount)) return null
    if (parent.type.spec.tableRole == "cell" || parent.type.spec.tableRole == "header_cell") {
      let cellPos = $head.before(d)
      let dirStr = axis == "vert" ? (dir > 0 ? "down" : "up") : (dir > 0 ? "right" : "left")
      return view.endOfTextblock(dirStr) ? cellPos : null
    }
  }
  return null
}

function domInCell(view, dom) {
  for (; dom && dom != view.dom; dom = dom.parentNode)
    if (dom.nodeName == "TD" || dom.nodeName == "TH") return dom
}

function cellUnderMouse(view, event) {
  let mousePos = view.posAtCoords({left: event.clientX, top: event.clientY})
  if (!mousePos) return null
  return mousePos ? cellAround(view.state.doc.resolve(mousePos.pos)) : null
}